Gladson Ricardo Flor Bertolini

Avaliação da força de preensão em ratos Wistar, normais e obesos, submetidos à natação com sobrecarga após compressão do nervo mediano

OBJECTIVE To verify the functionality through muscle grip strength in animals with obesity induced by monosodium glutamate (MSG) and in control animals, which suffered compression of the right median nerve, and treated with swimming with overload. METHODS During the first five days of life, neonatal Wistar rats received subcutaneous injections of MSG. The control group received a hypertonic saline solution. Forty-eight rats were divided into six groups: G1 (control); G2 (control + injury); G3 (control + injury + swimming); G4 (obese); G5 (obese + injury); G6 (obese + injury + swimming). The animals in groups G2, G3, G5 and G6 were submitted to compression of the median nerve and G3 and G6 groups were treated, after injury, with swimming exercise with load for three weeks. The swimming exercise had a progressive duration, according to the week, of 20, 30 and 40minutes. Muscle strength was assessed using a grip strength meter preoperatively and on the 3rd, 7th, 14th and 21st days after surgery. The results were expressed and analyzed using descriptive and inferential statistics. RESULTS When the grip strength was compared among assessments regardless of group, in the second assessment the animals exhibited lower grip strength. G1 and G4 groups had greater grip strength, compared to G2, G3, G4 and G6. CONCLUSION The swimming exercise with overload has not been effective in promoting improvement in muscle grip strength after compression injury of the right median nerve in control and in obese-MSG rats.

Comparison of continuous and pulsed ultrasound therapy in knee hyperalgesia of Wistar rats

BACKGROUND AND OBJECTIVES:Among electro agents ultrasound is one of the most common, however, there is insufficient evidence of the beneficial effects with the parameters currently used. The aim of this study was to compare the effect of continuous and pulsed ultrasound therapy on experimental hyperalgesia and edema in knees of Wistar rats.METHODS:18 rats were divided into three groups: CG- control group; GUP - treated with pulsed ultrasound 50%; and GUC - continuous ultrasound. To accomplish the lesion, animals were manually restrained and 100μL of 5% formalin solution were injected into the right tibiofemoral space. For assessment of nociception digital Von Frey filament was used on the medial side of the joint, until clinching. Edema was evaluated with mid-lateral knee caliper. Assessments occurred in the preinjury (EV1), after 15 (EV2), 30 (EV3) and 60 (EV4) minutes of the injury. After EV2, treatment was initiated with ultrasound with 0.4W/cm2 (SATA), pulsed or continuous.RESULTS:The CG had hypernociception, with no return to baseline. GUP has returned to baseline as from EV3 and for continuous ultrasound in EV4. All three groups showed similar behavior for edema, with onset in EV2, without reduction.CONCLUSION:Therapeutic ultrasound was effective to decrease nociception, and the pulsed form showed early results, however, both forms of application had no effect on the formation and maintenance of acute edema.

Comparison of combined therapy with ultrasound-associated interferential current in healthy subjects

BACKGROUND AND OBJECTIVES: Although used in the therapeutic field, there is a shortage of studies that evaluate combined therapy or the association of electrical currents with therapeutic ultrasound, the present study aimed to compare the two forms in healthy individuals, analyzing the pain, number of accommodations and current intensity. METHODS: Thirty healthy volunteers took turns for three weeks in three groups. Nociception was evaluated by means of pressure and thermal stimuli in the lumbar spine and respective dermatomes. Then, the volunteer’s dominant foot was submerged in cold water to evaluate the threshold of pain and its intensity. Shortly after, electroanalgesia (combined therapy, only current association with ultrasound, or placebo) was applied for 15 minutes. The application of the bipolar interferential current used a frequency of 4kHz, and amplitude modulation frequency of 100Hz, with one electrode on L3 and the other on S1. When combined therapy was used, the ultrasound head (1MHz) played the role of the electrode positioned over the L5-S1 region, in continuous form, at a dose of 0.4W/cm2. The intensity of the initial and final current was evaluated, as well as the number of accommodations. RESULTS: There was no significant difference between the pain thresholds of pressure and cold, but the combined therapy required more current intensity despite having a smaller number of accommodations. CONCLUSION: None of the therapies produced a difference in pain thresholds, but the combined therapy had fewer accommodations.

Behavioral assessment of rats through the forced-swimming test

Objetivos: O exercicio fisico regular tem diversos efeitos beneficos, contudo, ha relatos de aumento na concentracao de corticosteroides endogenos, os quais podem inibir a neurogenese e piorar as funcoes cognitivas, sendo este um aspecto dubio do exercicio fisico. O objetivo deste estudo foi avaliar, por meio de testes comportamentais, o efeito do exercicio cronico por natacao forcada com e sem sobrecarga, sobre parâmetros de ansiedade em ratos Wistar. Metodos: Foram utilizados 24 ratos Wistar, separados em tres grupos: Grupo Controle – submetido apenas a avaliacoes e contato com a agua; Grupo Natacao – composto por animais submetidos a natacao com tempo progressivo; Grupo Natacao com Sobrecarga – composto por animais submetidos a natacao com sobrecarga de 10% do peso corporal. O exercicio ocorreu tres vezes por semana, no periodo vespertino, com aumento no tempo a cada duas semanas (20, 30 e 40 minutos), totalizando seis semanas. Foi realizado em um tanque de agua circular de 200 litros, com profundidade de 50 cm e temperatura da agua mantida entre 30 e 32o C. A ansiedade dos animais foi avaliada pelos testes Labirinto em Cruz Elevado e Campo Aberto. Resultados: Nao houve diferencas significativas em qualquer dos testes comportamentais, comparando os tres grupos. Conclusoes: Nao houve alteracao no padrao comportamental de ratos Wistar submetidos a diferentes protocolos de exercicio (natacao forcada com e sem sobrecarga) quando comparados ao grupo controle nao submetido a exercicios

Nociceptive and histomorphometric characteristics of median nerves of rats with obesity induced by monosodium glutamate

Objetivos: Comparar a nocicepcao e, histomorfometricamente, a seccao transversa de nervos perifericos de ratos Wistar submetidos ao modelode obesidade induzida pelo glutamato monossodico com animais controle.Metodos: Foram utilizados ratos Wistar, divididos em grupo obeso e grupo controle. Desde o nascimento, durante os primeiros cinco dias devida, os ratos do grupo obeso receberam uma injecao diaria subcutânea de glutamato monossodico (4g/kg de peso corporal/dia), enquanto osratos do grupo controle receberam solucao salina hiperosmotica (1,25 g/kg de peso corporal/dia). Foi avaliada a nocicepcao, pelo limiar deretirada do membro, com uso de analgesimetro digital tipo Von Frey, com o estimulo dado na regiao palmar da pata anterior direita. A primeiraavaliacao foi realizada cerca de 20 dias antes da eutanasia, sendo a segunda avaliacao realizada no dia anterior ao da eutanasia. Posteriormente,foi dissecado o nervo mediano, na regiao do cotovelo e processado com cortes transversais para analise histologica. As variaveis analisadasforam: numero de axonios por campo; diâmetros dos axonios, das fibras e da bainha de mielina, e coeficiente G. Os resultados foram analisadospor meio do teste t de Student para amostras independentes e t pareado, com nivel de significância de 5%.Resultados: Foram estudados 14 ratos, sendo sete no grupo obeso e sete no grupo controle. A avaliacao da nocicepcao mostrou que osanimais do grupo obeso apresentavam menor limiar de retirada. Para os dados histomorfometricos, os resultados nao mostraram diferencassignificativas entre os dois grupos estudados.Conclusoes: Os animais obesos apresentaram menor limiar nociceptivo, porem nao houve diferencas morfometricas dos nervos medianosentre animais submetidos ao modelo de obesidade induzida pelo glutamato monossodico e os controles.(AU) Aims: To compare nociception and, histomorphometrically, the transverse section of peripheral nerves (median) of Wistar rats submitted toobesity model induced by monosodium glutamate with control animals.Methods: Fourteen Wistar rats divided into control and obese groups were used. During the five first days since birth the rats from obese groupreceived a daily subcutaneous injection of monosodium glutamate (4 g/kg body weight/day), while the control group received hypertonic saline(1.25 g/kg body weight/day). Nociception was evaluated by the withdrawal threshold of the limb, using digital analgesymeter type Von Frey,with the stimulus given in the palmar region of the right hind paw. The first assessment was carried out about 20 days before euthanasia, andthe second assessment was performed on the day before euthanasia. Subsequently the median nerve was dissected in the elbow region andprocessed with cross sections for histological analysis. The analyzed variables were: number of axons per ; axons, fibers and myelin sheathdiameters, and G coefficient. The results were analyzed using the t test for independent samples and paired t test, with a significance level of 5%.Results: Fourteen rats were assessed, being seven of the obese group and seven of control group. The evaluation of nociception showed thatthe animals of the obese group had lower withdrawal threshold. For histomorphometric data, the results showed no significant differencesbetween the two groups.Conclusions: The obese animals showed lower nociceptive threshold, however, there were no morphometric differences of the median nervesbetween animals subjected to the model of obesity induced by monosodium glutamate and the control group.(AU)

Use of high-voltage cathodic current for pain in experimental nerve compression

OBJECTIVE To assess the effect of high-voltage cathodic current on pain from a sciatica experimental model. METHODS A total of 16 male Wistar rats were submitted to the sciatica experimental model in the right hind paw. They were divided into sham group (GS) and group treated with cathodic current (GP-) for 20 min/daily, for 10 days). The model of sciatic compression was performed with a 4.0-chromic catgut thread tie in four points of the sciatic nerve. Assessment of nociception was performed by measuring the time during which the animal held its hind paw in a guarded position (THHP) and the pressure withdrawal threshold, by use of a digital electronic analgesymeter. Data collection was carried out before the sciatica experimental model (AS1), three days after compression (before, AS2, and after treatment, AS3), and five and 10 days after treatment (AS4 and AS5, respectively). RESULTS According to the functional disability test, both groups showed an increase in nociception, with no reduction at any assessment time. Submitted to pressure, however, GS showed a reduction in the hind paw withdrawal threshold at all assessment times, while GP- showed a reduction in the hind paw withdrawal threshold only initially - at AS5, the threshold was restored. CONCLUSION No change in nociception was observed on functional assessment; however, on pressure hind paw withdrawal assessment, the treatment with cathodic current showed to be effective with the summation of therapies.